Analysis of hard two-photon correlations measured in heavy-ion reactions at intermediate energies

Recently reported measurements of hard photon correlations in the reactions 36Ar on 27Al at 95A MeV, 86Kr on natNi at 60A MeV, and 181Ta on 197Au at 39.5A MeV are analyzed. A Boltzmann-Uehling-Uhlenbeck transport model is used to describe the photon production by individual nucleon-nucleon collisions. In the lighter systems we find the best agreement with data when taking into account only photons from first-chance collisions of nucleons or photons produced during the passage of the nuclei, while the model predicts also a considerable late-time emission of photons, which leads to a depletion of the calculated correlation function. The accuracy of the present data does not allow firm conclusions on the reliability of this late-time evolution. Our investigations do not support a recently reported interference pattern in the heavy Ta + Au system. copyright 1996 The American Physical Society